Prison guards in Costa Rica caught a pigeon with a bag of drugs attached to its chest in a bizarre attempt to smuggle drugs to inmates.

Officers at La Reforma prison captured it with 14g of cocaine and 14g of cannabis stuffed into a black pouch which camouflaged against its dark feathers.

They have previously caught other animals such as cats and iguanas trying to transport drugs into the prison in San Rafael de Alajuela, local websites have reported.

The guards spotted the bird on Tuesday afternoon as it flew towards an open area of the medium security La Reforma prison, Teletica reported.

Prison director Paul Bertozzi said: 'They observed the bulge on the animal so they captured it and confirmed that it carried a bag with zipper - and the drugs were inside... It seems the dove was trained for it.'

The pigeon was examined by experts at the ZooAve Animal Rescue Centre who said the bag it was carrying caused some damage to its digestive system.

Reports from Costa Rica suggest it will be kept in quarantine for at least 40 days because they believe it will return to where it came from if they release it.

The head of the centre was 'stunned' by the incident and said it would be well looked after at the centre.

The prison is now investigating who was responsible for the drug-smuggling attempt.

Paul Bertozzi added: 'We have a warning that this method can be used again as it is not the first time in the history of La Reforma that a pigeon was detected with drugs.'